Disinfectant efficacy against Candida auris is driven by formulation and concentration rather than clade-specific resistance.

BACKGROUND

Candidozyma auris (formerly Candida auris) is a multi-drug-resistant pathogen of global concern due to environmental persistence, biofilm formation, and limited treatment options. Disinfectant efficacy is variable, particularly under high organic load, with reports of reduced susceptibility to Candida albicans.

AIM: The aim of this study was to define the intrinsic chemical susceptibility of Candido auris clades I-IV and assess whether yeasticidal efficacy against Candida albicans predicts activity against Candido auris.

METHODS

Quantitative suspension tests (NEN-EN 13624:2022, dirty conditions) were used to evaluate six disinfectant chemistries: organic acid (lactic acid), halogen (chlorine), quaternary ammonium compounds, alcohol (ethanol), and oxidising agent (hydrogen peroxide). Testing was conducted in two independent laboratories using Candida albicans ATCC 10231 and Candido auris clades (I-IV).

FINDINGS: All chemistries achieved a ≥4 log10 reduction against Candida albicans and all Candido auris clades at validated conditions, with no consistent clade-dependent differences. Organic acid formulations showed comparable efficacy, highlighting a potential sustainable alternative.

CONCLUSION

Candido auris shows susceptibility comparable with that of Candida albicans. Efficacy is driven by formulation, concentration, and contact time rather than clade variation, supporting formulation-based disinfection strategies for healthcare settings.